Hoist, crane, lift, and the like lifting apparatus



S. BAYNES HOISTS, CRANES, LIFTS, AND THE LIKE LIFTING APPARATUS Fil ed Oct. 28, 1942 2 Sheets-Sheet l INVENTOR STAUNTON I BAYNES BY HIS ATTORNEYS April 3,1945; I s. BAYNES HOISTS, CRANES, LIFTS, AND THE LIKE LIFTING APPARATUS- 2 Sheets-Sheet 2 Filed Oct. 28, 1942 v Ina-enter 5h: 0/? fan 3/086 Patented Apr. 3, 1945 HOIST, CRANE, LIFT, AND THE LIKE LIFTING APPARATUS Staunton Baynes, Woodford Green, England, assignor to Asea Electric Limited, London, England, a British company a Application October 28, 1942, Serial No. 463,681

In Great Britain November 3, 1941 6 Claims.

This invention relates to hoists, cranes, lifts and the like lifting apparatus wherein there is a driving shaft capable of longitudinal movement and a. driven shaft in alignment therewith, between which shafts are friction surfaces associated with the said shafts and with an independent part, the arrangement being such that when the driving force ceases the driving shaft is immediately moved longitudinally towards the driven shaft thereby to cause the friction surfaces to engage each other and so brake the apparatus. When the apparatus is braked in this manner it is held by the said independent part. In the case where it is desired to lift or lower the load very small distances at very slow speeds, for instance at the commencement or conclusion of a lifting or lowering operation, special means have to be provided since the main motor cannot readily perform such a function. The known means to achieve this purpose called inching" is to make use of the said independent part by making it a rotatable member driven by an auxiliary motor which is operated when it is desired to carry out inching. In the known arrangement the rotatable member is an annular part mounted with a ball race, the balls running in a groove in the surrounding casing. Such a construction has proved unsatisfactory by reason of excessive Wear.

According to the present invention the rotatable member is a wheel turning on a central shaft or sleeve.

The accompanying drawings show how the invention may be carried out in practice as applied to an electric hoist. Figure 1 is a vertical section through the apparatus and Figure 2 shows a plan, partly in section, of the right-hand portion of Figure 1.

The hoist as shown in Figure l is provided with the usual pulley block I supported by a cable 2, one end 3 of which is anchored to the hoist, the other end of the cable being wound on a drum 4 which is rotated in one direction or the other to raise or lower the load. In actual practice there would be two such cables passing round the pulley block each anchored at one end to the hoistthe other ends being wound on the drum 4 in such manner as to distribute the load evenly about the centre of the length of the drum. A plan view of the winding arrangement is not shown since it is quite well known and forms no part of the present invention.

The drum 4 is rotated through w'orm or spur gear by means of a shaft 5, which is the driven shaft hereinbefore referred to, this shaft bein driven by the driving shaft 6 which in turn is rotated by the electric motor I. The hoist is provided with wheels 8 for running on a rail 9. The

drawing in Figure 1 also shows a lever I9 which is tripped by the pulley block I when the latter is raised to its upper limit, the lever then operating a switch to stop the supply of power to the electric motor 1, I The rotor II of the electric motor I has 7th shape of a 'frustum of a cone, the stator I2 being shaped to receive the rotor, as shown in Figure 1. A spring I3 presses on the end of the shaft 6 and tends to pushvthis shaft longitudinally towards the driven shaft 5 but when the motor is in operation the force of the spring I3 is counterbalanced by the force of the stator I2 upon therotor.

II, the rotor being pulled back by the stator so that it is more centrally positionedinside the stator. As soon as the supply of electric power to the electric motor is cut off, the spring I3 forces the shaft 6, i. e., the driving shaft referred to above, towards the driven shaft 5, t brake the apparatus.

The braking arrangement is as follows. The driving and driven shafts 6 and 5 respectively are in alignment, the end M of the shaft 6 slidably fitting in a hole I5 in the shaft 5. Mounted on the shaft 6 is a part I6 facing a part I1 which is mounted on the shaft 5. These parts are connected together by pins I8 which are fixed to the part I! and pass through holes in the part I6. When the shaft 6 and with it the part I6 is rotated, the rotary power is transmitted through the pins I8 to the part I! and thence to the shaft 5 but the part I6 is free to move longitudinally towards or away from the part II. Between the parts It and H are a number of friction discs I9, 20 and 2|, the disc 20 being loosely mounted on the pins I8 and the other discs I9 and 2| being loosely mounted on pins 22 fixed to a wheel 23. The wheel 23 is mounted on the part I1 and is free to rotate thereon. For this purpose the wheel is provided with a ball race 24 which is held in position by a collar 25 and an annular ring 26 bolted to the wheel by the bolts 21. The collar 25 holds the inside portion of the race against the flange 28 on the part I! and the ring 26 holds the outside portionof the race against the flange 29 on the Wheel 23.

The wheel 23 is provided with teeth on its periphery and is geared to an auxiliary motor 30, see Figure 2. The motor 30 is of the same type as the motor I. The shaft of the motor has an extension 3I into which slidably fits the end of a shaft 32. Mounted on the extension 3! is a part 33 which co-operates with a part 34 mounted on the shaft 32. Pins 35 are fixed on the part 33 and these pins pass through holes in the part 34. Rotary power can be transmitted from the shaft 3i to the shaft 32 through the part 33, the pins 35 and the part 34, but the part 33 can move towards or away from the part 34, the pins 35 moving in the holes in the part 34. Between the parts 33 and 34 is a stationary friction disc 36 held by the casing. When the motor is in operation power is transmitted to the shaft 32 as explained above but as soon as the supply of power to the motor is cut off the spring 31 forces the shaft of the motor to the left as viewed in the drawings, the part 33 then closing on the part 34 with the friction disc between the parts. As soon as the friction disc firmly engages the parts 33 and 34 they are brought to rest and the shaft 32 is then prevented from rotating. When the motor is operated again the rotor thereof is pulled to the right and the parts 33 and 34 separate with the friction disc becoming inoperative between them.

The shaft 32 has mounted thereon a toothed wheel 38 which engages a toothed wheel 39 which is mounted on ball-bearings 40 on a spindle 4|. The wheel 39 is geared to the wheel 23.

Referring now to Figure 1, the discs [9 and 2|, being held by the pins 22 which are fixed to the wheel 23, cannot be rotated except by the wheel itself but the discs are loosely mounted on the pins so that they are free to move in an axial direction. When the main motor I is in operation there is a slight clearance between the discs I9, 20 and 2| but as soon as the power to the motor is cut off the driving shaft 6 is forced axially towards the driven shaft 5 as explained above and the parts l6 and I! then force the discs together. Since the wheel 23 will at this time be held stationary the discs supported thereby cannot rotate and the friction discs and the parts It and I! will therefore be stopped from rotating thereby bringing the shafts 5 and 6 to rest.

If it is then desired to carry out the process known as inching, the auxiliary motor is operated to rotate the wheel 23 and it will be seen that since the friction discs I9, 20 and 2| are then in engagement, rotation of the wheel 23 will cause rotation of the shafts 5 and 6.

In the arrangement employed hitherto the construction of the mechanism whereby inching could be carried out was such that it was impossible to insert a feeler between the friction discs in order to ascertain the clearance therebetween. According to the present invention the wheel 23 is positioned at the side of the friction surfaces and there is no obstruction to prevent the insertion of a feeler. An opening 42 is therefore made in the casing to enable a feeler to be inserted.

on the'end 43 of the shaft 5 is an arrangement for adjusting the axial position of the shaft 5 to compensate for wear on the friction discs. This arrangement is fully described and claimed in the co-pending application No. 463,680, filed October 28, 1942, now abandoned.

What I claim is:

1. In lifting apparatus, a driving shaft capable of longitudinal movement, a driven shaft in alignment therewith, means connecting said driving shaft and said driven shaft whereby rotary motion can be transmitted from the driving shaft to the driven shaft, said means permitting longitudinal movement of the driving shaft toward or away from the driven shaft, a friction braking surface between said shafts, means connecting said friction braking surface with parts fixed to the adjacent ends of the shafts whereby said surface is rotated with the shafts, an independent friction braking surface between said shafts arranged for engagement with said first mentioned friction braking surface, an independent rotatable member rotatable independently of the shafts mounted for rotation on one of said shafts, means connecting said independent friction braking surface with said independent rotatable member, means to cause the driving shaft to move longitudinally towards the driven shaft immediately the driving force ceases to cause said friction surfaces to engage whereby rotary movement of the shafts is controlled by the independent rotatable member, and operating means for rotating said independent rotatable member for operating the apparatus at low speeds.

2. Apparatus according to claim 1, having the operating means for said independent rotatable member constructed and arranged to .prevent operation of said independent rotatable member when said independent rotatable member operating means is inactive.

3. Apparatus according to claim 1, having said independent rotatable member mounted for rotation on said driven shaft.

' 4. Apparatus according to claim 1, having said independent rotatable member mounted for rotation on a sleeve on said driven shaft.

5. Apparatus according to claim 1, having said independent rotatable member mounted for rotation on a rotary anti-friction bearing on said driven shaft.

6. Apparatus according to claim 1, characterised by the operating means for the independent rotatable member comprising an auxiliary motor having a longitudinally movable driving shaft, a; driven shaft in alignment therewith, means connecting said driving shaft and said driven shaft whereby rotary motion can be transmitted from the driving shaft to the driven shaft, said means permitting longitudinal movement of the driving shaft toward or away from the driven shaft, a friction braking surface between said shafts, means connecting said friction braking surface with parts fixed to the adjacent ends of the shafts whereby saidsurface is rotated with the shafts, an independent friction braking surface held against rotation between said shafts and arranged for engagement with the said first mentioned friction braking surface, means to cause the driving shaft to move longitudinally towards the driven shaft immediately the driving force ceases to cause said friction surfaces to engage whereby rotary movement of the shafts is prevented.

STAUNTON BAYNES. 

